Transcript Volcanoes and Igneous Activity Earth

Prentice Hall
EARTH SCIENCE
Tarbuck

Lutgens
Chapter
1
Introduction to
Earth Science
1.1 What Is Earth Science?
Overview of Earth Science
 Encompasses all sciences that seek
to understand
• Earth
• Earth's neighbors in space
1.1 What Is Earth Science?
Overview of Earth Science
 Earth science includes
1. geology, the study of Earth
2. oceanography, the study of the ocean
3. meteorology, the study of the atmosphere
and the processes that produce weather
4. astronomy, the study of the universe
1.1 What Is Earth Science?
Formation of Earth
 Most researchers conclude that Earth
and the other planets formed at
essentially the same time.
 Nebular Hypothesis
• The solar system evolved from an enormous
rotating cloud called the solar nebula.
1.1 What Is Earth Science?
Formation of Earth
 Nebular Hypothesis
• The nebula was composed mostly of
hydrogen and helium.
• About 5 billion years ago, the nebula began
to contract.
• It assumed a flat, disk shape with the
protosun (pre-Sun) at the center.
1.1 What Is Earth Science?
Formation of Earth
 Nebular Hypothesis
• Inner planets begin to form from metallic and
rocky clumps.
• Larger outer planets began forming from
fragments with a high percentage of ices.
The Nebular Hypothesis
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1.1 What Is Earth Science?
Formation of Earth
 Layers Form on Earth
• As Earth formed, the decay of radioactive
elements and heat from high-velocity impacts
caused the temperature to increase.
• Lighter rocky components floated outward,
toward the surface.
• Gaseous material escaped from Earth’s interior
to produce the primitive atmosphere.
1.2 A View of Earth
Earth's Major Spheres
1. Hydrosphere
• Ocean is the most prominent feature of the
hydrosphere.
- Is nearly 71% of Earth's surface
- Holds about 97% of Earth's water
• Also includes fresh water found in streams,
lakes, and glaciers, as well as that found
underground
1.2 A View of Earth
Earth's Major Spheres
2. Atmosphere
• Thin, tenuous blanket of air
• One half lies below 5.6 kilometers (3.5 miles)
3. Biosphere
• Includes all life
• Concentrated near the surface in a zone that
extends from the ocean floor upward for
several kilometers into the atmosphere
1.2 A View of Earth
Earth's Major Spheres
4. Geosphere
• Based on compositional differences, it
consists of the crust, mantle, and core.
- Crust—the thin, rocky outer layer of Earth.
- Mantle—the 2890-kilometer-thick layer of
Earth located below the crust.
- Core—the innermost layer of Earth, located
beneath the mantle.
Earth’s Layered Structure
1.2 A View of Earth
Plate Tectonics
 Plate tectonics is the theory that
proposes that Earth’s outer shell
consists of individual plates that interact
in various ways and thereby produce
earthquakes, volcanoes, mountains, and
Earth’s crust itself.
1.3 Representing Earth’s Surface
Determining Location
 Latitude and longitude are lines on the
globe that are used to determine
location.
• Latitude is distance north or south of the
equator, measured in degrees.
• Longitude is distance east or west of the
prime meridian, measured in degrees.
1.3 Representing Earth’s Surface
Maps and Mapping
 No matter what kind of map is made,
some portion of the surface will always
look either too small, too big, or out of
place. Mapmakers have, however, found
ways to limit the distortion of shape, size,
distance and direction.
1.3 Representing Earth’s Surface
Topographic Maps
 Topographic maps represent Earth’s
surface in three dimensions; they show
elevation, distance directions, and slope
angles.
• Contour lines are lines on a topographic
map that indicate an elevation.
• Contour interval is the distance in elevation
between adjacent contour lines.
1.4 Earth System Science
What Is a System?
 A system is any size group of interacting
parts that form a complex whole.
 Closed systems are self contained
(e.g., an automobile cooling system).
 Open systems allow both energy and matter
to flow in and out of the system
(e.g., a river system).
1.4 Earth System Science
Earth as a System
 Earth is a dynamic body with many
separate but highly interacting parts
or spheres.
 Earth system science studies Earth
as a system that is composed of
numerous parts, or subsystems.
1.4 Earth System Science
Earth as a System
 Sources of Energy
• Sun—drives external processes such as
weather, ocean circulation and erosional
processes
• Earth’s interior—drives internal
processes including volcanoes,
earthquakes and mountain building
1.4 Earth System Science
Earth as a System
 Consists of a nearly endless array of
subsystems (e.g., hydrologic cycle)
 Humans are part of the Earth system.
1.4 Earth System Science
People and the Environment
 Environment
• Surrounds and influences organisms
• Physical environment encompasses water,
air, soil, and rock
• The term environmental is usually reserved for
those aspects that focus on the relationships
between people and the natural environment.
1.4 Earth System Science
People and the Environment
 Resources
• Include water, soil, minerals, and energy
• Two broad categories
1. Renewable—can be replenished (e.g.,
plants, energy from water and wind)
2. Nonrenewable—cannot be replenished in
the near future (e.g., metals, fuels)
1.4 Earth System Science
People and the Environment
 Population
• Population of the planet is growing rapidly
• Use of minerals/energy has climbed more
rapidly than the overall growth of population
Growth of World Population
1.4 Earth System Science
Environmental Problems
 Local, regional, and global
 Caused by people and societies
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Urban air pollution
Acid rain
Ozone depletion
Global warming
 Caused by natural hazards
• Earthquakes
• Landslides
1.5 What Is Scientific Inquiry?
Science
 Science assumes the natural world is
• consistent
• predictable
 Goals of science are
• to discover patterns in nature
• to use the knowledge to predict
1.5 What Is Scientific Inquiry?
Hypothesis and Theory
 An idea can become a
• hypothesis—tentative or untested explanation
• theory—tested, confirmed, supported hypothesis
 Scientific Method
• Gather facts through observation
• Formulate hypotheses
• Test hypotheses to formulate theories
1.5 What Is Scientific Inquiry?
Science Methods
 Scientific knowledge is gained through
• following systematic steps
1. Collecting facts
2. Developing a hypothesis
3. Conducting experiments
4. Reexamining the hypothesis and accepting,
modifying, or rejecting it
• theories that withstand examination
• totally unexpected occurrences